1. Field of the Invention
The present invention relates to an RF (radio frequency) aperture coldplate.
2. Description of Related Art
RF systems have been developed to provide information of a scene or other useful data to a user or other system. RF systems may be adapted to function at different frequency bands. For example, RF systems such as radar and communication systems may operate in the X-band (8.0-12.0 GHz) or the Q-band (40.0-60.0 GHz), respectively. Sub-bands of these established bands may be used for specific purposes. For example, satellite communication systems may operate in the 40.0-45.0 GHz sub-band of the Q-band (40.0-60.0 GHz). One of ordinary skill in the art would understand that RF systems may function in one or more frequency bands.
Depending on the specific application, RF systems may be mounted in a variety of vehicles (e.g., air, ground, sea), ground stations (or other suitable permanent or semi-permanent ground fixtures), or satellites (or other spacefaring vehicles). One of ordinary skill in the art would understand that an RF system designer chooses hardware and integrates software to be used for operation with these specific applications in mind. For example, an RF system operating in the satellite communications sub-band of the Q-band may require hardware and software specifically developed for the physical and electrical characteristics of generating and propagating RF signals in the 40.0-45.0 GHz frequency band.
RF systems generally utilize antennas to transmit and receive RF signals. For example, RF systems utilize reflectors, horns, dipoles, phased arrays, and other antenna elements. RF systems using antenna arrays usually require an antenna plate to arrange the antenna elements. Certain RF systems that use circular elements perform in tandem with circular waveguides formed in the antenna plate itself.
Modern RF systems generally are cooled with air or liquid. Coldplates are formed as plates with hollow passages inside to circulate cooling medium (e.g., air or liquid) near heat generating elements of an RF system. For example, monolithic microwave integrated circuits (MMICs) generate a high amount of heat, and a coldplate may be used to draw heat away from such heat generating elements to increase performance or reduce component failure. Generally, it is advantageous to place the coldplate as close to heat generating elements as possible.
A traditional RF system includes a printed circuit board (PCB) composed of copper, which includes electrical components and wiring to generate and route the RF signals. Such RF systems typically have coldplates mechanically fixed to the PCB. Because the coldplate must mate securely, there is typically very little mechanical tolerance between the PCB and the coldplate. In an RF system where it is desirable to use an antenna plate having circular waveguides, the antenna plate must also be securely fixed to the PCB (on the opposite side of the coldplate). There is typically very little mechanical tolerance between the PCB and the antenna plate. Such systems are generally built from the back to the front, such that a coldplate is fixed to a PCB copper plate on one end and an antenna plate is fixed to the PCB copper plate on the other end. Both PCB/coldplate and PCB/antenna plate interfaces must mate securely. If there are gaps in the PCB/coldplate interface, there is a decrease in cooling performance. If there are gaps in the PCB/antenna plate interface, there is a decrease in electrical interface performance.